The present invention relates to hand-holdable pyrotechnic devices commonly referred to as xe2x80x9csparklersxe2x80x9d, and to a method of manufacture of sparklers.
Fireworks are often on display on festive occasions. Among prominent displays is the 4th of July holiday in the U.S., and fireworks displays are often part of celebrations at other times and worldwide, such as at the New Year holiday each year, at Halloween, and at various sporting events. One fireworks product often seen at such displays is the hand-held sparkler.
A sparkler is a device that emits brilliant sparks upon burning. Conventional sparklers generally are made of a long, thin stick or metal wire having a flammable, spark-emitting coating, e.g., a phosphorous compound, thereon. When the coated end of the sparkler remote from the hand hold is ignited, e.g., with a match, lighter, punk, etc., the coating ignites, sparks are randomly emitted as the ignition point travels down the wire, usually for a few minutes, and the spark burns out when it reaches the end of the coating and before contacting the hand of the user. Many holiday revelers are attracted to and enjoy using and/or viewing sparklers, which devices have been known, generally, for centuries.
The present invention provides a new form of sparkler and a method for its manufacture. This new sparkler has an extended burning time, and thus a concomitant extended time for enjoyment, over conventional sparklers of the same length. Also, in one embodiment of the invention, the sparkler burns for a time emitting sparks of one color, and the direction of burning of the spark reverses itself and then burns for a time emitting sparks of a color different from that of the initial burn. The need and desirability of the novel sparklers of this invention are readily apparent.
An article of manufacture suitable for use in a sparkler fireworks display is provided. The sparkler of this invention includes an elongate central core having a first coating thereon of an ignitable, flammable, spark-emitting-upon-ignition material. This first coating extends along the length of the core a first distance from one end thereof, the distal end, leaving a portion of the core bare at the proximate end thereof opposite the one end, the bare portion acting as a hand-hold thereof. The core and first coating have a second coating thereon extending along the outside of the first coating from and including the one end, along the length thereof extending a second distance from the one end, this second coating being of a fire resistant material. The core, first coating and second coating have a third coating thereon, wherein the third coating is of an ignitable, flammable, spark-emitting-upon-ignition material. The third coating extends as a sheath along the outside of and along the length of the core and first and second coatings to a third distance from and including the distal end. The first and third distances both exceed the second distance. Optionally, and optimally, the third distance of coating coverage exceeds the first distance of coating coverage.
The central core may be a wire, preferably an iron wire, or it may be a stick, such as a wooden stick. The bare portion of the core is sufficiently long to enable hand holding of the sparkler. The core may have a length of approximately one foot or, alternatively, the core may have a length which exceeds one foot.
The first ignitable coating material is one which produces a selected one of the spark colors of red, green, yellow, silver or gold, upon ignition, and the third coating is of a material which produces a selected one of the spark colors of red, green, yellow, silver or gold, upon ignition. The first ignitable coating material and the third coating material may be selected such that two different-colored sparks are produced by the materials upon ignition. In a preferred embodiment, the first ignitable coating material is one which emits gold sparks upon ignition and the third coating material is selected such that sparks are produced upon ignition thereof of a selected one of the colors red, green, yellow and silver.
A process for making sparklers is also provided. The process includes securing a plurality of elongate cores in a holder therefore, each core being releasably held in the holder proximate one end of the core. Each core extends essentially vertically downwardly from the holder such that a substantial length of all of the cores extends, exposed, downwardly and outwardly from the holder. The holder and secured elongate cores are dipped into a first dip tank containing a coating composition of a material which, after coating and drying, is ignitable, flammable and spark-emitting, and the holder and secured coated cores are withdrawn and dried. Optionally, the dipping into this first dip tank, withdrawing and drying, are repeated, as desired, to increase the amount of coating applied to each core. The coated cores are then dipped into a second dip tank containing a coating composition of a fire resistant material, this dipping being to a lesser depth within the coating composition than in the first dipping. The coated cores are withdrawn and dried, followed by dipping of the holder and secured, coated cores into a dip tank containing a coating composition of a material which, after coating and drying, is ignitable, flammable and spark-emitting. This dipping step subjects the cores to a greater dipped depth within this composition than in the previous dipping into the fire resistant composition. The holder and secured coated cores are withdrawn and dried. Optionally, this dipping, withdrawing and drying is repeated, as desired.
The plurality of dipped, coated and dried cores are released from the holder, thereby producing a plurality of fireworks display articles, namely a plurality of sparklers.
Any one of the flammable, spark emitting coating compositions may comprise a slurry of potassium perchlorate, magnesium aluminum alloy, strontium carbonate, a binder resin and ethanol, to produce red sparks on ignition. Alternatively, the coating composition may be a slurry of potassium perchlorate, barium nitrate, magnesium aluminum alloy, a binder resin and ethanol (green sparks), a slurry of barium nitrate, magnesium aluminum alloy, potassium perchlorate, Cryolite, sulfur and water (yellow sparks), or potassium perchlorate, barium nitrate, magnesium aluminum alloy, sulfur and water (silver sparks) or barium nitrate, iron, aluminum, phenolic resin and water (gold sparks).
The fire resistant coating composition preferably comprises a solution of a phenolic resin, pentaerythritol and triammonium phosphate, most preferably 35% phenolic resin, 50% pentaerythritol and 15% triammonium phosphate.
The drying may be air drying, oven drying or any other suitable drying method.